Western blot showing binding of MoAb 17 to chimeric α3/α1(IV)NC1 domains. COS supernatants from transfected cells were separated on 12.5% SDS–PAGE gels and electroblotted to nitrocellulose. Recombinant chimeric human α3/α1(IV)NC1 domains were detected with 1:100 dilution of MoAb W17. Lane 1 contained collagenase-solubilized (cs) human glomerular basement membrane (GBM) as a positive control. The recombinant protein in the other lanes was: lane 2, human α3(IV)NC1 (α333); lane 3, α113; lane 4, α131; lane 5, α311; lane 6, α331; lane 7, α313; lane 8, α133.